A genome-wide RNAi screen identifies novel targets of neratinib sensitivity leading to neratinib and paclitaxel combination drug treatments

Abstract

ErbB2 is frequently activated in tumors, and influences a wide array of cellular functions, including proliferation, apoptosis, cell motility and adhesion. HKI-272 (neratinib) is a small molecule pan-kinase inhibitor of the ErbB family of receptor tyrosine kinases, and shows strong antiproliferative activity in ErbB2-overexpressing breast cancer cells. We undertook a genome-wide pooled lentiviral RNAi screen to identify synthetic lethal or enhancer (synthetic modulator screen) genes that interact with neratinib in a human breast cancer cell line (SKBR-3). These genes upon knockdown would modulate cell viability in the presence of subeffective concentrations of neratinib. We discovered a diverse set of genes whose depletion selectively impaired or enhanced the viability of SKBR-3 cells in the presence of neratinib. We observed diverse pathways including EGFR, hypoxia, cAMP, and protein ubiquitination that, when co-treated with RNAi and neratinib, resulted in arrest of cell proliferation. Examining the changes of these genes and their protein products also led to a rationale for clinically relevant drug combination treatments. Treatment of cells with either paclitaxel or cytarabine in combination with neratinib resulted in a strong antiproliferative effect. The identification of novel mediators of cellular response to neratinib and the development of potential drug combination treatments have expanded our understanding of neratinib's mode-of-action for the development of more effective therapeutic regimens. Notably, our findings support a paclitaxel and neratinib phase III clinical trial in breast cancer patients.

Profile of neratinib and its potential in the treatment of breast cancer

“…These results, as well as those of the study from Seyhan et al28 point to the potential added benefit of using neratinib as a combinational treatment option alongside other targeted treatments as well as conventional chemotherapeutics.…”

“…In a study using a panel of cell lines, we showed that the response to neratinib was correlated with baseline HER2 and phosphorylated HER2 levels, but not with EGFR levels in vitro 26. Interestingly, neratinib decreased the activation of phosphatidylinositide 3-kinase and mitogen-activated protein kinase downstream pathways, and the activity against AKT and ERK could be correlated with efficacy 14,26,28. Other biomarker candidates that have been investigated in vitro include upregulation of RB1CC1, HER3, FOXO3a, and NR3C1 as well as downregulation of CCND1 mRNA, all of which have been correlated with response to neratinib 29.…”

Neratinib Reverses ATP-Binding Cassette B1-Mediated Chemotherapeutic Drug Resistance In Vitro, In Vivo, and Ex Vivo

“…The 16-week PFS rate was 45%, and the median PFS duration was 19 weeks. It is noteworthy that the findings of Seyhan et al (2011) support a phase III clinical trial of neratinib with paclitaxel among patients with breast cancer. Three large phase III clinical trials using neratinib are currently ongoing.…”

New protein kinase inhibitors in breast cancer: afatinib and neratinib

“…Recently, preclinical data have shown that lapatinib is a substrate of multidrug efflux transporter P-glycoproetin (ABCG1), which is located at the BBB and may account for the decreased CNS penetration of lapatinib [71]. Studies have shown that neratinib can reverse ABCG1-mediated multidrug resistance [72] and it was unaltered by the presence of ABCG2 transporter [73]. Based on these results, neratinib has the potential to pass BBB and effectively treat CNS metastasis.…”